Biology 1002B Lecture Notes - Lecture 25: Color Vision, Pax6, Cone Cell
Document Summary
Bio 1002b - lecture 25 evolution of colour vision. Why did eye evolve so many times: eyes have many selective advantages ability see food and predators. Pax6 = family of transcription factors crucial in embryonic development, especially in sensory organ development (including eye: pax6 originated before animals developed, pax6 sequences from divergent animals show same domains. Cone cells (photoreceptor cells) are attributed to colour vision. Every cone cell has millions of molecules of rhodopsin. Three different types of cone cells each contain different type of rhodopsin (3 different types of rhodopsin) Rhodopsin can be categorized into short wavelength (sensitive to blue light), medium wavelength (sensitive to green light and yellow light a little), and long wavelength (sensitive to yellow light: highest sensitivity to green light. Biochemical explanation for trichromatic vision: pigments (retinal biosynthetic pathway) are identical, but opsin proteins are different. Sw, mw, lw opsin are homologous, there are many areas of absolute conservation when sequences are aligned.
